High precision edge ring centering for substrate processing systems

Abstract

An edge ring centering system for a plasma processing system includes a processing chamber including a substrate support and R edge ring lift pins, where R is an integer greater than or equal to 3. An edge ring includes P grooves located on a bottom surface thereof, where P is an integer greater than or equal to R. A robot arm includes an end effector. A controller is configured to cause the optical sensor to sense a first position of the edge ring on the end effector; cause the robot arm to deliver the edge ring to a first center location on the edge ring lift pins; retrieve the edge ring from the edge ring lift pins; and cause the optical sensor to sense a second position of the edge ring on the end effector.

What is claimed is: 
     
         1 . An edge ring centering system for a plasma processing system, comprising:
 a processing chamber including a substrate support and R edge ring lift pins, where R is an integer greater than or equal to 3;   an edge ring including P grooves located on a bottom surface thereof, where P is an integer greater than or equal to R;   a robot arm including an end effector;   an optical sensor; and   a controller configured to:
 cause the optical sensor to sense a first position of the edge ring on the end effector; 
 cause the robot arm to deliver the edge ring to a first center location on the edge ring lift pins; 
 retrieve the edge ring from the edge ring lift pins; and 
 cause the optical sensor to sense a second position of the edge ring on the end effector. 
   
     
     
         2 . The edge ring centering system of  claim 1 , wherein the controller is further configured to generate a first offset based on a difference between the second position and the first position. 
     
     
         3 . The edge ring centering system of  claim 2 , wherein the controller is further configured to generate a first adjusted center location for the edge ring based on the first center location and the first offset. 
     
     
         4 . The edge ring centering system of  claim 3 , wherein the controller is further configured to:
 cause the robot arm to deliver the edge ring onto the edge ring lift pins based on the first adjusted center location;   retrieve the edge ring from the edge ring lift pins; and   cause the optical sensor to sense a third position of the edge ring on the robot arm.   
     
     
         5 . The edge ring centering system of  claim 4 , wherein the controller is further configured to generate a second offset based on a difference between the third position and the second position. 
     
     
         6 . The edge ring centering system of  claim 5 , wherein the controller is further configured to generate a second adjusted center location based on the first adjusted center location and the second offset. 
     
     
         7 . The edge ring centering system of  claim 6 , wherein the controller is further configured to:
 cause the robot arm to deliver the edge ring onto the edge ring lift pins based on the second adjusted center location;   retrieve the edge ring from the edge ring lift pins; and   cause the optical sensor to sense a fourth position of the edge ring on the robot arm.   
     
     
         8 . The edge ring centering system of  claim 7 , wherein the controller is further configured to generate a third offset based on a difference between the fourth position and the third position. 
     
     
         9 . The edge ring centering system of  claim 8 , wherein the controller is further configured to compare the third offset to a predetermined offset. 
     
     
         10 . The edge ring centering system of  claim 8 , wherein the controller is further configured to determine whether the edge ring is centered based on the comparison. 
     
     
         11 . The edge ring centering system of  claim 1 , wherein the P grooves are “V”-shaped. 
     
     
         12 . The edge ring centering system of  claim 1 , wherein the P grooves are spaced 360°/P around the bottom surface of the edge ring. 
     
     
         13 . The edge ring centering system of  claim 1 , wherein the P grooves are “V”-shaped and wherein a bottommost portion of the P grooves extend in a radial direction.